CDC conducts science-based investigations, research, and public health surveillance both nationally and internationally.
CDC adopts recommendations that are made by the Advisory Committee for Immunization Practices.
All 2016-2017 influenza vaccines are made to protect against the following three viruses: Some of the 2016-2017 flu vaccine is quadrivalent vaccine and also protects against an additional B virus (B/Phuket/3073/2013-like virus). Vaccines that give protection against three viruses are called trivalent vaccines.
Vaccines that give protection against four viruses are called quadrivalent vaccines.
So an annual vaccination is needed to get the “optimal” or best protection against the flu.
Optimally, vaccination should occur before onset of influenza activity in the community.
The recommendations for vaccination of people with egg allergies have changed for 2016-2017. The effectiveness of influenza vaccine against influenza A (H3N2) virus infections in nursing homes in Niigata, Japan, during the 1998--19--2000 seasons. Cunney RJ, Bialachowski A, Thornley D, Smaill FM, Pennie RA. Effects of influenza vaccination of health-care workers on mortality of elderly people in long-term care: a randomised controlled trial. Effectiveness of influenza vaccine in health care professionals: a randomized trial. Both trivalent (three-component) and quadrivalent (four-component) flu vaccines will be available.